var cities = [{
    id: 1,
    name: '北京',
    collapse:false,
    children:[
        {
            id:11,
            name:'东城区'
        },{
            id:12,
            name:'西城区'
        },
    ]
}, {
    id: 2,
    name: '天津',
    collapse:false,
    children:[
        {
            id:21,
            name:'和平区'
        }, {
            id:22,
            name:'南开区'
        }
    ]

},{
    id: 3,
    name: '成都',
    collapse:false
}]